Geometric Leftover Hat is designed to be made with small bits of leftover yarn. None of the balls of yarn I used were bigger than my fist, and as you go along, you will have opportunities to switch to using other yarns if you are running out of one of your colors.
This hat can be made with three or more colors, and in addition to having a chart, also provides instructions on designing and making your own geometric leftover hat.

This hat can be made to any size, but Adult only is featured in these instructions.

Additionally, you can use any yarn to make this hat, make sure the gauge matches, or add/decrease stitches to get the desired size.

Happy Knitting!